[Violet89]

A first order reaction has an activation energy of 68.1 kJ/mol and a frequency factor (Arrhenius constant) of 1.48 x 1012 sec -1. Calculate the rate constant at 18°C.

K = A * exp(- Ea / RT)

I understand what to plug into this equation, but I keep getting the wrong answer. I calculate (- Ea / RT), press 2nd + LN, and multiply that by A. Am I doing something wrong?

I'd appreciate any help.

[argulor]

Are you using R= 0.008314 KJK^-1mol^-1?

[sjb]

Are you using R= 0.008314 KJK^-1mol^-1?

...or T=18, or a frequency factor of ~ 1500?

[Borek]

I calculate (- Ea / RT), press 2nd + LN

On my TI that would mean calculating natural logarithm, not [itex]e^{\frac {-E_a} {RT}}[/itex].